Development is through aplacental viviparity. Thresher sharks’ color varies from metallic brown to blue on their dorsal (upper) sides and white on their ventral (under) sides. A contribution to the natural history of the white-tip shark, Sharks of the east coast of Southern. "Global phylogeography of thresher sharks (. Fishing pressure may include being caught in its nursery areas. [13] A rete system is present around the pelagic thresher's brain and eyes, albeit less developed than in the bigeye thresher, which may serve to buffer those organs against temperature changes. Oiver, S. (2005). Sutaria, Dipani Significant reductions in thresher CPUE have been reported in pelagic longline fisheries in the northwest Atlantic and the eastern tropical Pacific, and declines are also suspected to have occurred in other areas. Learn how your comment data is processed. The reproductive biology of the pelagic thresher shark Alopias pelagicus, was analysed based on 241 individuals (101 males and 140 females).Samples were collected from April 2005 to February 2006, from the artisanal fishery in Manta, Ecuador.
The largest records having been caught in New Zealand waters, while light-tackle thresher records have been set off California. Reproductive biology and population dynamics of the shortfin mako.
Though uncommon in US fish markets, threshers are consumed in other parts of the world (valued for their meat, liver, hide, and fins; utilized fresh, dried-salted, smoked, and frozen). eISSN: 1765-2952
Direct evidence for oophagy in thresher shark, Canadian Journal of Fisheries and Aquatic Sciences, R: A language and environment for statistical computing, Review of the biology of the tiger shark (. The Bigeye Thresher Shark (Alopias superciliosus) apparently is a highly migratory, oceanic and coastal species found virtually circumglobally in tropical and temperate seas. The teeth are smooth-edged, with oblique cusps and lateral cusplets on the outside margins.
This species has been recorded to reach 500 cm (16.4 ft), but this figure is questionable and may have resulted from confusion with other threshers. Sex ratios of sampled specimens were biased to males in pelagic thresher, bigeye thresher, tiger shark and blue shark, while females dominated in the specimens of oceanic whitetip shark. He illustrated one of the three specimens in his paper, "On the two species of the thresher shark from Formosan waters", published in August 1935. Nakamura also separately illustrated and described a fetus, that Leonard Compagno later concluded was probably of a common thresher. No furrows occur at the corners of the mouth. Although data are lacking for many parts of its range, it is evident that this Vulnerable species, with such low productivity, faces major threats throughout most of its range, where fishing pressure is unlikely to cease or decrease anytime in the immediate future. Pups have a fast growth rate and are born in open water. The habitat of this species is poorly known. 2020. The first dorsal fin is placed halfway between the pectoral and pelvic fins, and is of comparable size to the pelvic fins.
The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species. Part 1.
[12] A single female produces about 40 young over her entire life.
The shortfin mako shark. This species is abundant off the northeastern coast of Taiwan. Other language common names for this species include: cá nhám duôi dài (Vietnamese), hwan-do-sang-o (Korean), kleintand-sambokhaai (Afrikaans), kooseh-e-derazdom (Farsi), nitari (Japane… A record of 5 m (16.4 ft) is dubious and may have resulted from confusion with other thresher species. Predators of the pelagic thresher probably include large predatory fishes (including other sharks) and toothed whales (Cetacea: Odontoceti) inhabiting the same geography and habitat.
A total of 4371 bigeye threshers were recorded throughout the Atlantic Ocean between 1992 and 2013, with the sizes ranging from 70 to 305 cm FL (fork length).
Pelagic Thresher Shark, Alopias pelagic Hawaiian Name: Manō hi’ukā (“Smiting tail”) Habitat: Open ocean Maximum Size: 10.8 feet Danger to humans: Minimal, due to habitat Notes: Thresher and mako sharks are commonly sold at the fish auction in Honolulu. They have sometimes been measured at over 5m but this is due to the ease of confusion with Common Threshers and is not true. The specific name pelagicus is derived from the Greek word pelagios meaning “of the sea”.
There is evidence that thresher sharks are being increasingly targeted by pelagic fisheries for swordfish and tuna (e.g., in the Mediterranean Sea) in attempts to sustain catches, and exploitation is increasing in these areas. The oldest confirmed ages for females and males are 16 and 14 years, respectively.
This species is rarely targeted except in the central Pacific and northwestern Indian oceans, but is often caught as a bycatch on floating longline gear set for other sharks, tunas, or swordfish. [14], The pelagic thresher has never been implicated in an attack on humans; it has small jaws and teeth for its size and tends to flee from divers. [4], CS1 maint: multiple names: authors list (, Trejo, T. (2005). The pelagic thresher is lighter in color than the other thresher species. Late stage embryos are devoid of teeth, and then grow them shortly before birth. and Age, growth, and reproduction of the pelagic thresher shark. The pelagic thresher is able to elevate its body temperature above that of the water around it by using a special circulatory system.
Threshers are often caught on longlines with their caudal fins snagged on the hook after striking the bait with the upper caudal fin tip. This is the method of reproduction for the “live-bearing” fishes where pups hatch from egg capsules inside the mother’s uterus and are born soon afterward. This site uses Akismet to reduce spam. 3. Lengths at maturity for males were in the range of 189.05–286.56 cm, whereas those of females were in the range of 187.74–310.69 cm. The color rapidly fades to gray after death. Notes on the reproduction of the Oceanic Whitetip Shark, Collective Volume of Scientific Papers - ICCAT, Sharks of the world. Males reach sexual maturity at 2.7 m, females at 3 m. Litters usually consist of 4-6 pups measuring between 1.14-1.60 m in length and weighing between 5-6 kgs at birth. Pelagic threshers are valued by commercial fisheries for their meat, skin, liver oil, and fins, and are also pursued by sport fishers. (2008). Only the upper half of the tail fin is long, the lower is much more proportional to the size of the shark. Young, Chelsey N. In this study, the size structure, sex and maturity of pelagic thresher (Alopias pelagicus), bigeye thresher (A. superciliosus), oceanic whitetip shark (Carcharhinus longimanus), tiger shark (Galeocerdo cuvier), shortfin mako (Isurus oxyrinchus), longfin mako (I. paucus) and blue shark (Prionace glauca) in the eastern Arabian Sea are described based on 1449 specimens collected from gillnet-cum-longline landings at the Cochin fisheries harbour during 2013–2014. An overview of the hooking mortality of elasmobranchs caught in a swordfish pelagic longline fishery in the Atlantic Ocean Aquat. Extrapolating the growth curves to the largest known individuals suggests that females may have a lifespan exceeding 28 years, and males 17 years. This map was computer-generated and has not yet been reviewed. The pelagic thresher contains ten percent of its total body weight as liver weight. The sex ratio of young is 1:1. Gravid females in various stages of pregnancy were recorded throughout the year from off northeastern Taiwan. Females matured at greater lengths than males in all species except oceanic whitetip shark. pelagic thresher ( Alopias pelagicus ), the litter size of the bigeye thresher is commonly two (rarely four) pups, though they grow more slowly and reach maturity at a later age than the other threshers (Moreno and Morón, 1992; Mancini & Amorim, 2006; Romero-Caicedo, 2007, Smith et al., 2008a). The largest known Thresher Sharks reach a length of more than 6 meters (20ft) and weigh 600 kilograms (216 pounds). 25, 311–319 (2012) The teeth are very small, numbering 21–22 rows on each side with a symphysial (central) row in the upper jaw and 21 on each side without a symphysial row in the lower jaw. Magalon, Hélène Each capsule measures about 55 mm (2.2 in) long and 12 mm (0.5 in) across, and contains 20–30 ova. Sexual maturity is usually reached around 250-300 cm, with maximum reported size around 365 cm TL. These visits occur more frequently early in the morning, and may be why these normally oceanic sharks are sometimes encountered in shallow water.
13570). Dermal denticles located alongside the body have cusps that point posteriorly. Comparing him with the mako, he is pound for pound, a harder fish to whip”.
Although this species is reportedly relatively common in some coastal localities, current levels of exploitation in some areas are considered to be unsustainable. There is also a smaller third species of thresher shark called pelagic or fine-tooth threshers, Alopias pelagicus. Carlson, John K. It has low fecundity (2-4 pups/litter) and an exceptionally low (0.002) potential annual rate of population increase, compared with other thresher sharks.
Distribution data is imprecise due to confusion with the common thresher, and the pelagic thresher may occur over a wider area than is presently known. Five to 11 rows of posterior teeth are present. Males and females attain known maximum lengths of 3.5 m (11.5 ft) and 3.8 m (12.5 ft), respectively. The generic name Alopias is derived from the Greek word alopexmeaning “fox”.
The oil from the liver, known as squalene oil, is sometimes used in the manufacture of cosmetics, health foods, and high-grade machine oil. The bigeye thresher, Alopias superciliosus, is next in size, reaching a length of 4.9 m (16 ft); at just 3 m (10 ft), the pelagic thresher, Alopias pelagicus, is the smallest. Thresher sharks are ovoviviparous.
Juvenile threshers are often found close inshore and in shallow bays.
Average size is about 300 cm (10 ft) and 69.5 kg (153.3 lb). Dentition The behaviour of pelagic thresher sharks (, International Union for Conservation of Nature, "The red muscle morphology of the thresher sharks (family Alopiidae)", Species Description of Alopias pelagicus at www.shark-references.com, https://en.wikipedia.org/w/index.php?title=Pelagic_thresher&oldid=980544801, Creative Commons Attribution-ShareAlike License, This page was last edited on 27 September 2020, at 03:38.
Size, Age & Growth
[3] The specific epithet pelagicus is from the Greek pelagios, meaning "of the sea". Along with all other mackerel sharks, the pelagic thresher exhibits ovoviviparity and usually gives birth to litters of two.
Its very slender tail and fine dentition suggest an exclusive diet of small, pelagic prey.
It is not known if this species ascends the water column at night, as does the bigeye thresher, Alopias superciliosus.
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